In written parliamentary answers the Foreign Secretary revealed that although he had decided not to keep on Anne Bullen, his predecessor's secretary, on 21 May, he had not decided to employ a career civil servant until 30 May.
Ms Bullen, who was appointed by Douglas Hurd and retained by Malcolm Rifkind, was told that Ms Regan was being considered for the post when it was decided that her contract would not be renewed.
Although an official then spoke to Ms Regan on the telephone about her possible appointment, no contract was ever drawn up, Mr Cook said in reply to questions from Conservative MPs.
The appointment caused controversy after Ms Bullen claimed that she was sacked in favour of Ms Regan. Mr Cook said that Ms Bullen was "impossible" to work with.
Mr Cook also disclosed further details of the October weekend on which he flew back from the royal visit to India and Pakistan. There had been allegations that he flew to Britain and back to Asia to spend time with Ms Regan. In a reply to Howard Flight, Tory MP for Arundel and South Downs, he said he returned to Britain because he had no further official business in Pakistan. He spent 18 hours working on official papers and spent a day in his Livingston constituency.Reuse content